| 摘要 |
A client terminal is provided with a column encryption unit that, from an encryption key, a table identifier, and a column identifier, generates a column private key, a column public key, and a comparison value, from which the unit generates a concealed comparison value and a ciphertext, encrypting a particular column; and an encrypted table natural joining request unit that issues a natural joining request text that requests natural joining with regards to columns encrypted from the encryption key, the table identifier, and the column identifier. The natural joining request text contains as a table joining key the column private key generated by a group of generating elements and the encryption key from the table identifier of a first and second table and the column identifier of an a-th column and a b-th column. An encrypted database server executes natural joining using the table joining key, and returns the results. |
